I use buns all the time, my ends are already smooth because they're relaxed but they're starting to break off. I don't really care about my ends because each month i cut of some of my relaxed ends. I use Shea moisture smoothie and carol's daughter tui oil to moisture before i twist or braid my hair at night.

Buns can be very useful, but be careful about your edges if they have a tendency to be weak. I rotate buns with other styles to reduce the strain on my hairline. If you start with a ponytail to bun, move it around to prevent breakage at that spot, and soak the ponytail holder in oil before putting it on to reduce friction Last, keep the ends oiled well to prevent splits. Other than that, enjoy!

(Oh, and I mean that in all sincerity. I'm fully natural, and I use buns quite frequently, for at least 6 months straight because of the ease, so these tips are just from my experience about the pros and cons of them.)